I doubt Herbert will be of any help. Chet passed long ago and Doug may not be old enough to have any info from his Dad's products from 60 years ago.
Chet was a cool guy. Member Wyrmryder knew him I'm sure. He was confined to a wheelchair but ran his shop everyday. He was so busy his phone would ring off the hook until about 8pm before he'd answer. I used his cams in my Ford dirt cars for several years.